Cold-Atom Clocks as Part of a Timing Ensemble

We describe a space cold atom clock prototype and its operation on board an aircraft. We have recorded the atomic resonance in zero gravity during parabolic flights. This experiment must be considered as an essential step toward the construction of a space clock using cold atoms. In a microgravity environment, a cold atomic clock would outperform all ground-based clocks. By the year 2002, we plan to operate a cold atom clock on board the international space station. This mission is called Atomic Clock Ensemble in Space (ACES). We have also performed a preliminary accuracy evaluation of the prototype. The interrogation of the cold atoms is performed inside a TE/sub 013/ cavity. On earth, the phase variations of the field induce a relative frequency shift of about 1/spl times/10/sup -13/. Although the frequency shift is expected to strongly decrease in microgravity, this cavity does not seem suitable for a 1/spl times/10/sup -16/ frequency uncertainty.We describe a space cold atom clock prototype and its operation on board an aircraft. We have recorded the atomic resonance in zero gravity during parabolic flights. This experiment must be considered as an essential step toward the construction of a space clock using cold atoms. In a microgravity environment, a cold atomic clock would outperform all ground-based clocks. By the year 2002, we plan to operate a cold atom clock on board the international space station. This mission is called Atomic Clock Ensemble in Space (ACES). We have also performed a preliminary accuracy evaluation of the prototype. The interrogation of the cold atoms is performed inside a TE/sub 013/ cavity. On earth, the phase variations of the field induce a relative frequency shift of about 1/spl times/10/sup -13/. Although the frequency shift is expected to strongly decrease in microgravity, this cavity does not seem suitable for a 1/spl times/10/sup -16/ frequency uncertainty.

IEEE Transactions on Instrumentation and MeasurementApr 1, 199914 citations

Atomic Clocks and Cold Atom Scattering

Chad Fertig, Ronald Legere, J.Irfon Rees +3 more

Springer eBooksJan 1, 20031 citation

Quantum-noise-limited interferometric measurement of atomic noise: Towards spin squeezing on the Cs clock transition

Daniel Oblak, Plamen G. Petrov, Carlos L. Garrido Alzar +5 more

We investigate theoretically and experimentally a nondestructive interferometric measurement of the state population of an ensemble of laser-cooled and trapped atoms. This study is a step toward generation of (pseudo)spin squeezing of cold atoms targeted at the improvement of the cesium clock performance beyond the limit set by the quantum projection noise of atoms. We calculate the phase shift and the quantum noise of a near-resonant optical probe pulse propagating through a cloud of cold $^{133}\mathrm{Cs}$ atoms. We analyze the figure of merit for a quantum nondemolition (QND) measurement of the collective pseudospin and show that it can be expressed simply as a product of the ensemble optical density and the pulse-integrated rate of the spontaneous emission caused by the off-resonant probe light. Based on this, we propose a protocol for the sequence of operations required to generate and utilize spin squeezing for the improved atomic clock performance via a QND measurement on the probe light. In the experimental part we demonstrate that the interferometric measurement of the atomic population can reach a sensitivity of the order of $\sqrt{{N}_{\mathrm{at}}}$ in a cloud of ${N}_{\mathrm{at}}$ cold atoms, which is an important benchmark toward the experimental realization of the theoretically analyzed protocol.We investigate theoretically and experimentally a nondestructive interferometric measurement of the state population of an ensemble of laser-cooled and trapped atoms. This study is a step toward generation of (pseudo)spin squeezing of cold atoms targeted at the improvement of the cesium clock performance beyond the limit set by the quantum projection noise of atoms. We calculate the phase shift and the quantum noise of a near-resonant optical probe pulse propagating through a cloud of cold $^{133}\mathrm{Cs}$ atoms. We analyze the figure of merit for a quantum nondemolition (QND) measurement of the collective pseudospin and show that it can be expressed simply as a product of the ensemble optical density and the pulse-integrated rate of the spontaneous emission caused by the off-resonant probe light. Based on this, we propose a protocol for the sequence of operations required to generate and utilize spin squeezing for the improved atomic clock performance via a QND measurement on the probe light. In the experimental part we demonstrate that the interferometric measurement of the atomic population can reach a sensitivity of the order of $\sqrt{{N}_{\mathrm{at}}}$ in a cloud of ${N}_{\mathrm{at}}$ cold atoms, which is an important benchmark toward the experimental realization of the theoretically analyzed protocol.

arXiv:quant-ph/0312165Physical Review AApr 11, 200577 citations

Cold atom space clock with counter-propagating atoms

吕德胜, 汪斌, 李唐 +1 more

Chinese Optics LettersJan 1, 20100 citations

^{133}\mathrm{Cs}

atoms. We analyze the figure of merit for a quantum nondemolition (QND) measurement of the collective pseudospin and show that it can be expressed simply as a product of the ensemble optical density and the pulse-integrated rate of the spontaneous emission caused by the off-resonant probe light. Based on this, we propose a protocol for the sequence of operations required to generate and utilize spin squeezing for the improved atomic clock performance via a QND measurement on the probe light. In the experimental part we demonstrate that the interferometric measurement of the atomic population can reach a sensitivity of the order of

\sqrt{{N}_{\mathrm{at}}}

in a cloud of

{N}_{\mathrm{at}}

cold atoms, which is an important benchmark toward the experimental realization of the theoretically analyzed protocol.